New Methods Monitor Health-related Loss in Salmon

NORWAY - Arnfinn Aunsmo showed in his doctorate that health-related loss in modern salmon farming may be systematically monitored and quantified, both in biological and economical terms.

The salmon farming industry is characterised both nationally and internationally by large swings in profitability, a large part of which is due to health-related challenges. However, in order to address health-related problems and use resources optimally, it is first necessary to find out how health status influences biological production. This has now been down, thanks to Aunsmo's own field studies and analyses of selected private and public databases.

The doctorate describes biological and economic models for quantification of health-related loss in salmon farming. It further describes how health-related loss may be monitored systematically both at farm level and by the industry as a whole. The statistical methods used in these analyses of information from salmon farming are innovative and world-class.

Specific causes of death were investigated in a study of 10 localities from Rogaland to Troms. The study forms a basis for a description of methods of quantitative monitoring of causes of death in aquaculture.

Better methods of mapping side-effects

In two studies, vaccines were found to be risk factors for spinal deformities in salmon. Fish with spinal deformities had in addition a significant growth rate reduction. In addition, it was shown in one study that the use of oil-based vaccines leads to a weight loss of 0.5 kg in slaughter-weight salmon. The work describes better methods of mapping the side-effects of fish vaccines.

The expense of an outbreak of pancreas disease (PD) on the Norwegian west coast was in one economic model calculated to be NOK 14,400,000 for a typical farm with some 500,000 smolts. This economic model can be used for general economic evaluations of health effects and in coast-benefit analyses of counter-measures.

This doctoral work was carried out at the Centre of Epidemiology and Biostatistics of the Norwegian School of Veterinary Science, in close collaboration with private companies such as Marine Harvest, SalMar, Pharmaq, AquaGen, and others, and regulatory bodies such as the National Veterinary Institute and the Norwegian Food Safety Authority.

5m Editor

It is vital that fish farm operatives who are responsible for farmed fish are trained in their health and
welfare. This will help to ensure that fish are free from disease and suffering whilst at the same time
promote good productivity and comply with legislation.